Separation Control in the ALL APT Light Pipe.
Abstract
An experiment was performed to determine separation regions inside a high energy laser (HEL) beam relay light pipe. The pipe is part of the beam relay system used in conjunction with the CO2 Gas Dynamic Laser (GDL) system under development by the Air Force Weapons Laboratory. It was found that the air flowing through the pipe separated at the elbows. This separation can cause uneven radial heating attributed to molecular absorption. The self-induced thermal distortion of the beam can cause phase distortions degrading the beam. A study of separation control systems within the pipe was made. A full-scale axisymmetric model was studied on the water table. Areas of separation were found by flow visualization using dye injection. A brief evaluation of suction and blowing to control separation showed both of these methods acceptable. Separated regions discovered at each elbow on the water table were the focus of study for a full-scale air flow plexiglass model. The turbulent flow in the pipe was studied using smoke injection to reveal air motion in the pipe. Mass flow rates of air through the pipe were 1 lb/min and 8 lbs/min. Suction and blowing were assessed as flow separation control methods.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1979
- Accession Number
- ADA079904
Entities
People
- Wade H. Bailey Jr
Organizations
- Air Force Institute of Technology